Decanting apparatus

ABSTRACT

A DECANTING APPARATUS WITH HEAT EXCHANGER AND QUIESCENT CHAMBERS IS DESCRIBED. THE INLET CHAMBER IS CONNECTED VIA A PRODUCT CHAMBER OF A SPIRAL HEAT EXCHANGER TO A DISCHARGE CHAMBER DISPOSED ROUND THE HEAT EXCHANGER, THE SAID PRODUCT CHAMBER BEING NARROW AS COMPARED TO ITS HEIGHT AND BEING ARRANGED IN SEVERAL TURNS ROUND THE INLET CHAMBER.

Jan. 19, 1971v G; @RAME-R ET AL DECANTING, APPARATUS Filed June :5,V 1969 2 m El H m K ACW www@ OCHA M TMN NAMEN V HN@ WHUE E@ BYZ L?? .gel/

ATTORNEYS United States lPatent O M 3,555,820 DECANTING APPARATUS Gerhard Cramer, Frankfurt am Main, and Gunter Heck and Egon Malow, Hofheim, Taunus, Germany, assignors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lucius & Bruning, Frankfurt am Main, Germany, a corporation of Germany Filed June 3, 1969, Ser. No. 829,860 Claims priority, application Germany, June 21, 1968, 1,767,836 lut. Cl. B01d 19/00 U.S. Cl. 55-177 4 Claims ABSTRACT F THE DISCLOSURE A decanting apparatus with heat exchanger and quiescent chambers is described. The inlet chamber is connected via a product chamber of a spiral heat exchanger to a discharge chamber disposed round the heat exchanger, the said product chamber being narrow as compared to its height and being arranged in several turns round the inlet chamber.

The present invention provides a decanting apparatus with quiescent chambers and heat exchanger. The apparatus is used for separating and degassing liquid dispersions while cooling or heating.

The decanting apparatus of the invention is particularly intended for the separation of dispersions that are obtained after the condensers in azeotropic rectifications and similar processes, for example steam rectifications.

For the separation of such dispersions, decanting apparatus as they have been known from extraction plants have hitherto been used. These decanting apparatus generally are simple containers arranged in a vertical or horizontal position, which serve as quiescent chambers. Decanting apparatus provided with baille and guide plates have also been used in extraction plants to favor the separation process.

When using these decanting apparatus for the separation of liquid phases as they are obtained after the condenser in an azeotropic rectification, particularly in the case of binary heterogeneous azeotropes, the decanting apparatus is connected to a heat exchanger.

With the help of the heat exchanger the temperature of the dispersion is adjusted to the range of a reduced reciprocal solubility of the liquids. In other cases, the heat exchanger is used to prevent a change of phase, for example a separation of a component of the mixture or dispersion by vaporization or occulation. The heat exchangers are generally disposed after the condenser and before the decanting apparatus and are designated aftercoolers because a reduction of temperature is desired in the case of most of the mixtures that are interesting in industry.

The choice of the heat exchanger and the height at which it should be disposed with respect to the decanting apparatus pose problems which could not hitherto be y or if an immersed operation is obtained in some other way, an unsatisfactory flow is obtained or the dispersion ows through jerkily because bags are then inevitably ICC formed in which layers of the heavier liquid deposit, thus impeding the flow of the dispersion,

One has been hesitant so far about combining the heat exchanger and the decanting apparatus in-to one apparatus, for example, by disposed a cooling device in or at the decanting apparatus, as it was feared that the convection currents produced by such devices might counteract the desired separating action.

Now we have found that the above disadvantages can be avoided by using a decanting apparatus provided with a heat exchanger and quiescent chambers, in which the inlet chamber is connected via the product chamber of a spiral heat exchanger to a discharge chamber disposed round the heat exchanger, the said product chamber being narrow as compared to its height and being arranged in several turns round the inlet chamber.

The apparatus in accordance with the invention requires only a small floor space and has small over-all dimensions. Connection pipes between the heat-exchanger and the decanting apparatus are dispensed with. In the narrow product chamber of the heat exchanger only feeble convection currents which are of no importance for the sedimentation process are produced.

The level of the liquid in the apparatus may be adjusted by appropriately arranging the short discharge pipe for the lighter liquid phase. The said short discharge pipe is preferably disposed at such a height that a gas space is left above the surface of the liquid. More advantageously, an adjustable weir is disposed in the discharge chamber, which enables the apparatus to be more readily adjusted to another product or to changes in the mode of operation.

To reduce a convection current which may be possibly formed in the inlet and discharge chambers to a degree in which it becomes ineffective, the walls that come into contact with the liquid may be coated with a material of poor caloric conductibility. The discharge chamber is advantageously insulated on the outside if high working temperatures are used.

A decanting apparatus constructed in accordance with the invention will now be described in more detail by way of example with reference to the accompanying drawings of which:

FIG. 1 is a vertical section through the decanting apparatus in accordance with the invention, and

FIG. 2 is a horizontal section of the decanting apparatus shown in FIG. 1.

The central inlet chamber 1 is connected Ivia the product chamber 2 of the spiral heat exchanger to the discharge chamber 3 arranged concentrically with the inlet chamber 1. The level of the liquid in the chambers is determiined by the position of the Weir 4.

The short inlet pipe for the dispersion forms an immersion tube 5. From chamber 1 the already partially separated dispersion flows through the inlet gap 6 into the product chamber 2 of the heat exchanger. The sedimentation process is continued during the long spiral passage through chamber 2, of which only a few turns Vare vShown in the drawing for the sake of simplicity. The distance between the side walls in the product chamber is only a few millimeters and is advantageously within the range of from 6 to 30 millimeters, depending on the throughput and the properties of the dispersion. When a large throughput is used it is advantageous to increase the height but not the breadth of the product chamber.

The inlet to the outer quiescent chamber is formed by the outlet gap 7 of chamber 2 and is near the partition wall 8 which, together with partition wall 9, forms a cooling agent distributor or a collecting box.

The lighter product flows via the Weir 4 and the discharge box 11 to the short discharge pipe 12. The heavier product is drawn olf in a low site before the Weir. The

cooling agent is generally conducted from the collecting box to the discharge collector 13 in a direction opposite to the direction of motion in the product chamber. Vapors and gases from the liquid phases of the dispersion are removed through the short degassing pipe 14.

A boundary-layer regulator of known type as it is necessary in continuously operated decanting apparatus is shown in dotted lines. The short discharge pipe 12 for the lighter product may be provided with a level control means for the discharge box 11, for example, in the form of an upward loop 16. To simplify the drawing, the coatings and the external insulation are not shown.

The decanting apparatus of the invention is not only applicable to rectification plants. It may also be used for extraction plants and in all cases in which it is intended to separate liquid dispersions up to the very limit given by the reciprocal solubility.

What is claimed is:

1. A decanting apparatus provided with heat exchanger and quiescent inlet, product and discharge chambers for the continuous separation and degassing of dispersions with simultaneous heating or cooling, in which the inlet chamber is connected via the product chamber of a spiral heat exchanger to the discharge chamber disposed around the heat exchanger, the said product chamber being narrow as compared to its height and being arranged in sev- 4 eral turns around the inlet chamber an inlet associated with the inlet chamber and outlets for separated gas and separated liquids associated Awith the discharge chamber.

2. The decanting apparatus of claim 1, wherein the discharge chamber is provided with'an adjustable Weir.

3. The decanting apparatus of claim 1, wherein the walls of the inlet and discharge chambers that come into contact with the liquid are coated `with a material of poor caloric conductibility. v

4. The decanting apparatus of claim 1, wherein the distance between the side walls of the product chamber is within the range of from 6 to 30 millimeters.

References Cited UNITED STATES PATENTS 1,109,103 9/1914 Baum 55--175 2,353,138 7/1944 Beach 55-175X 2,706,015 4/ 1955 Bills 55-175 SAMIH N. ZAHARNA, Primary Examiner R. W. BURKS, Assistant Examiner U.S. Cl. X.R. -175 

